Inhibitory effects of 17aα-D-homo ethynylestradiol-3-acetate combined with γ-ray irradiation on adenocarcinoma of the lung in different mice strains

Abstract

Objective To study the inhibitory effects of 17aα-D-homo ethynylestradiol-3-acetate (DHEA) combined with 137Cs γ-ray irradiation on adenocarcinoma of the lung in different mice strains.Methods The LA795 tumor were diluted by saline to the cell suspension at the concentration of 3.5×107/ml.Each IRM-1 and IRM-2 mice was transplanted by armpit injection of 0.2 ml cell suspension.After 24 h,the mice were randomly divided into control group,radiation alone group,DHEA treated groups (high,middle and low dose respectively) and DHEA combined with irradiation groups.Mice in DHEA treated groups and combination groups were intraperitoneally injected with DHEA daily for 7 days.Mice in the combination groups were irradiated with 1 Gy per day for 5 days after injected with DHEA for 4 days.The anti-tumor effects of DHEA combined with irradiation on different group were measured.Results The tumor inhibitory ratios of IRM-1 mice in DHEA treated groups were 38.05％ (low does),49.33％ (middle dose) and 48.18％(high does) respectively,while in combination groups were 56.98％ (low does),64.44％ (middle dose) and 62.72％ (high dose).Compared with control group,the tumor inhibitory ratios in DHEA treated groups (t =3.417,4.929 and 4.889,all P＜0.01) and combination groups (t=5.475,5.770 and 6.165,all P＜0.01)were elevated.The tumor inhibitory ratios of IRM-2 mice in DHEA treated groups were 42.73％ (low dose),70.91％ (middle dose) and 67.73％ (high dose) respectively,while in combination groups were 63.63％ (low dose),75.00％ (middle dose) and 68.64％ (high dose).Compared with control group,the tumor inhibitory ratios in DHEA treated groups (middle and high dose) (t=3.239 and 3.062,both P＜0.01 )and combination groups (t=2.834,3.426 and 3.156,P＜0.05,＜0.01 and ＜0.01) were elevated.Conclusions DHEA showed tumor inhibitory effects on different mice strain transplanted with tumor.The synergistic anti-tumor effects of DHEA and γ-ray irradiation were more effective than DHEA alone. Key words: Gamma rays; Lung neoplasms; 17aα-D-homo ethynylestradiol-3-acetate; IRM-1 mouse; IRM-2 mouse